Software Troubleshooting · Topic 3 of 5
Mobile OS and App Problems
Troubleshoot phones and tablets that will not charge, run slowly, overheat, lose wireless signal or have crashing apps, including swollen battery safety.
- 4 min
- Charging problems: try another cable and charger, then clean the port, then replace the battery.
- A swollen battery is a safety risk. Stop using it and recycle it.
- Overheating is reduced by removing the case and closing heavy apps.
What it is
Mobile devices fail in different ways from desktops. Many problems come from battery, charging, wireless connections or apps, and the repair options are limited because parts are often sealed in. The same troubleshooting method applies, but the usual steps are restart, update, reset settings and replace parts.
How it works
Device and hardware symptoms
| Symptom | Likely causes | Common steps |
|---|---|---|
| Will not charge | Bad cable or adapter, dirty or damaged port, weak battery | Try another cable and charger, clean the port gently, check for a loose connector, replace the battery |
| Will not power on | Dead battery, hardware failure | Charge for a while, try a forced restart, then inspect hardware |
| Slow performance | Too many apps, low storage, old operating system (OS) | Close apps, free storage, update, restart |
| Short battery life | Heavy apps, bright screen, weak battery | Check battery use, lower brightness, remove heavy apps, replace an old battery |
| Overheating | Heavy use, charging, case, failing battery | Remove the case, stop heavy tasks, let it cool |
| Frozen system | App or OS fault | Force restart, update, factory reset if it keeps happening |
| Cracked screen or no touch response | Damage or software | Replace the screen, or restart and test the touch |
| Screen does not rotate | Rotation lock or sensor issue | Check the setting, restart |
| Weak or no cellular signal | Location, carrier, subscriber identity module (SIM) issue | Toggle airplane mode, reseat the SIM, check coverage |
A swollen battery is a safety issue. The battery has gassed and may swell the case. Stop using and charging the device, do not puncture or press the battery, and have it replaced or recycled through a proper channel.
Random reboots
A phone that restarts on its own may have a failing battery, overheating, a faulty app or update, or very low storage. Try these steps in order.
- Remove the most recently installed apps.
- Update the operating system and apps.
- Start in safe mode to see whether a third party app is the cause.
- Back up, then factory reset.
- Replace the battery if the problem continues.
Wireless and connectivity problems
If Wi-Fi, Bluetooth or cellular data does not work, first confirm that airplane mode is off. Toggle the radio off and on, forget and rejoin the Wi-Fi network, and move closer to the access point.
For Bluetooth, remove the pairing and pair again, and check that the other device is in pairing mode. For mobile data, check the plan, the data setting and the APN (access point name) settings.
For Near Field Communication (NFC), such as contactless payment, check that NFC is turned on. A thick case or metal object can block the signal, and the phone must be held within a few centimetres of the reader. Confirm that the payment app is set as the default.
App problems
| Symptom | Steps |
|---|---|
| App will not launch | Restart the device, update the app, clear its cache, reinstall |
| App crashes or runs slowly | Force stop, update, clear cache and free storage |
| App will not update or sync | Check the connection, storage space and account sign in |
| Email or contacts do not sync | Check the account settings, password and sync options |
| Apps no longer work after OS update | Check for an app update, or reinstall |
Clearing an app's cache removes temporary data and keeps user data. Clearing its stored data resets the app and removes local settings. A device in safe mode on Android loads only the original apps, which helps show whether a third party app is the cause.
Escalating steps
A factory reset erases the device, so back up data first. Use it when other steps fail or before the device is passed on. If the hardware is damaged, repair or replace the part, or the device.
If a battery is swollen, do not charge the device or keep it near heat, and do not try to flatten it.
What to remember for the exam
- Charging problems: try another cable and charger, then clean the port, then replace the battery.
- A swollen battery is a safety risk. Stop using it and recycle it.
- Overheating is reduced by removing the case and closing heavy apps.
- For wireless problems, check airplane mode, then toggle, forget and rejoin.
- Bluetooth problems are fixed by unpairing and pairing again.
- App problems: restart, update, clear cache, reinstall.
- Factory reset is a late step and needs a backup.
- Keep the OS and apps updated.
Common mistakes
Replacing the device first. A cable, charger or restart often solves the problem.
Charging a swollen battery. This is a hazard. Stop and replace it.
Forgetting airplane mode. It turns off the cellular, Wi-Fi and Bluetooth radios by default.
Resetting without a backup. The user loses data that could have been saved.
Check yourself
What should you do first when a phone will not charge?
Try a different cable and charger, then inspect the port.
What does clearing an app cache remove?
Temporary data, while user data and settings stay.
What is the correct response to a swollen phone battery?
Stop using and charging it, and have the battery replaced and recycled safely.
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